Add blank group-level security configuration page, navigation

What does this MR do and why?

Add group-level security configuration page

Add feature flag, licensed feature, and custom ability
Add sidebar menu item that links to group security configuration page
Add page that renders a vue app with title and tab
Only show menu item and page if
- feature flag is enabled for the top-level group
- licensed feature is available
- user has admin_security_labels permission

• add tests
• add detail to description
• fix https://gitlab.com/gitlab-org/gitlab/-/pipelines/1892456331/failures
• frontend review
• frontend maintainer review
• backend review
• backend maintainer review
• groupauthorization maintainer review (required for /ee/app/policies/ changes)

References

• issue: Frontend: Scaffold group-level `Security config... (#550472 - closed)
• epic: Security Attributes/Context Filtering (&18010)
• design: #547963[Security_configuration_-_group-level_-_security_labels_-_category_details_-_full_edit.png]
• https://docs.gitlab.com/development/permissions/custom_roles/#how-to-add-support-for-an-ability-to-custom-roles

Screenshots or screen recordings

Case	Before	After
feature flag enabled for the root group AND licensed feature available AND user authorized to admin_security_labels for the root group	no menu item, no page
feature flag disabled for the root group OR licensed feature not available OR user not authorized to admin_security_labels for the root group	no menu item, no page

How to set up and validate locally

0. run this command with ID replaced by the ID of a root group that you have at least the maintainer role in:

   git checkout 550472-set-up-group-security-configuration-page-with-security-labels-tab
   echo "Feature.enable(:security_context_labels, Group.find(ID))" | gdk rails c

1. navigate to the group or any of its subgroups
2. in the sidebar choose Secure => Security configuration (new menu item)
3. a Security configuration page should be shown with a single Security labels tab that contains only a description for now
4. impersonate a user who has the developer role in the root group
   5. navigate to the group or any of its subgroups
   6. Secure => Security configuration should not be shown in the sidebar
   7. if you navigate to the page anyway (/groups/path/to/group/-/security/configuration), it should show 403: You do not have the permission to access this page
5. if the feature flag is not enabled for the group's root ancestor group, the page should show 403: You do not have the permission to access this page
6. if the group does not have a GitLab Ultimate license, the page should show 403: You do not have the permission to access this page

to run tests

bundle exec rspec ee/spec/helpers/groups/security_features_helper_spec.rb ee/spec/lib/sidebars/groups/menus/security_compliance_menu_spec.rb ee/spec/policies/group_policy_spec.rb ee/spec/requests/groups/security/configuration_controller_spec.rb

MR acceptance checklist

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